His recent dominance on the world's richest golf tour – Day has won four out of his past six events – means the Queenslander is one of only five players who can win the "FedEx Cup" by saluting in next week's final tournament of the year.

For the uninitiated, the FedEx Cup is golf's version of the AFL premiership and next week on the schedule is the grand final – the Tour Championship.

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If Day were to win that event, the 27-year-old would win the US$10 million bonus prize for clinching the FedEx Cup, as well as another US$1.485 million payday for the victory itself.

No Australian golfer has ever won the FedEx Cup, and therefore never pocketed that sort of single-day payment. It's hard to think of any Australian sportsperson who has done so.

From humble beginnings, Jason Day, pictured with son Dash and wife Ellie, is in a rich vein of form Photo: Getty Images

If he were able to, it would catapult his yearly income into another stratosphere – US $20,274,805, or $28,196,263 Australian.

It would essentially be AUD $16 million in one day, and when combined with the $2 million he won on Monday, that would then grow to around $18 million in the space of seven days.

It would make an already inspiring story that much more incredible when you consider Day's humble beginnings.

To give it some context, NBA basketballer Andrew Bogut was Australia's highest-earning sportsperson in 2014 with AUD$16.2 million, according to the most recent BRW annual top 50 list.

In fact, Day is a strong chance to match Bogut's bounty even if he doesn't win this week.

Sitting clear on top in the FedEx Cup standings, there are only a limited number of scenarios that could knock him down with only seven days to go.

There is a realistic scenario where Day could win the US$10 million bonus by finishing in the top five, maybe even the top 10.

And even taking into account the worst-case scenarios, a respectable finish is likely to keep him in at least the top five positions - all of which have a US$1 million-or-more bonus attached to them.

For instance, if Day were to be bumped down to second on the overall standings, he would still receive a US$3 million payout plus whatever prizemoney he earns for whatever position he finishes in the Tour Championship tournament.

Under that scenario, Day's total packet for 2015 could balloon to in excess of AUD$16 million, the equal of Bogut.

And that's not including the sponsorship and endorsement deals that already generate a healthy dividend for him, and more that are certain to come his way now that he is game's hottest commodity.

Two sports marketing experts contacted by Fairfax Media on Monday said Day's new no.1 ranking could be worth several million dollars to him in new endorsement and related deals in the future.